To date, a large number of plant cultivation methods to accelerate the plant growth such as the methods utilizing superabsorbent polymers represented by crosslinked sodium polyacrylate gels (Patent Literature 1), foamable resins represented by polyvinyl alcohols, polyurethanes and polystyrenes (Patent Literature 2), and breathable films and porous films represented by non-woven fabrics, or multi films (Patent Literature 3 and Patent Literature 4) have been reported.
But the cases that the amount of water or a nutrient solution required depending on the plant growth cannot be supplied have been observed in the cultivation method utilizing superabsorbent polymers, the cases that the air necessary for the plant growth cannot be sufficiently supplied have been observed in the cultivation method utilizing formable resins, and the cases that the amount of water or a nutrient solution necessary for the plant growth cannot be retained and therefore stably supplied to plants have been observed in the cultivation method utilizing breathable films or porous films.
A cultivation method utilizing ceramics (Patent Literature 5) was discovered in order to solve the aforementioned problems. But the capability of this method to supply to plants the amount of water or a nutrient solution necessary for the plant growth has been still insufficient, and thus, no plant cultivation environment for plants to absorb the amounts of the elements necessary for the plant growth as much as plants want whenever plants want has not been provided yet.